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The Performance Comparisons between the Unconstrained and Constrained Equalization Algorithms

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The Journal of china Universities of posts and telecommunications 2003年第4期10卷 50-58页

作者： HE Zhong-qiu,LI Dao-ben(school of information engineering, {3. University of posts and telecommunications, beijing 100876, P. R. china) school of information engineering Beijing University of Posts and Telecommunications 北京 100876

This paper proposes two unconstrained algorithms, the Steepest Decent (SD)algorithm and the Conjugate Gradient (CG) algorithm, based on a superexcellent cost function. At thesame time, two constrained algorithms which include the Constrained Steepest Decent (CSD) algorithmand the Constrained Conjugate Gradient algorithm (CCG) are deduced subject to a new constraincondition. They are both implemented in unitary transform domain. The computational complexities ofthe constrained algorithms are compared to those of the unconstrained algorithms. Resultingsimulations show their performance comparisons.

关键词： transform domain adaptive equalization constrained equalization algorithm

Relaying Selection with Network-coded Cooperative Protocols in Aeronautical communications

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Chinese Journal of Aeronautics 2010年第1期23卷 75-83页

作者： Du Bing,Zhang Jun school of Electronics and information engineering,{3. University of Aeronautics and Astronautics,{3. 100191,china [a] school of Electronics information engineering Beijing University of Aeronautics Astronautics Beijing 100191 China

In this article, we exploit the idea of network-coded cooperative protocol in aeronautical communications which combines different source nodes＇ information at the relay and joint decoding at the destination. Recently, the network coding in cooperative communications has been categorized into two mainstreams, bit-level and signal-level combinations, which are both discussed in the article. And to be exclusively,multiple access relay channel（MARC） is adopted. The mutual information expressions of both above-cited network-coded protocols are deduced, which prove that without proper selected relays to perform network coding, the spatial diversity of the proposed protocol cannot be obtained. This then leads to search for the selection and grouping algorithms. An adjacency matrix is defined to describe the connectivity of the nodes in one radio contact disk, so that, the selection and grouping of algorithm is equivalent to constructing this adjacency matrix to minimize the system outage probability evaluated in term of the mutual information. Besides, a network-coded cooperative protocol requires the acyclic network, of which the construction is to avoid loop-4 in the matrix. The article ends with simulations to demonstrate the viability of the proposed algorithms.

关键词： communication network coding outage probability mutual information bit-level signal-level

基于对角隐式Runge-Kutta公式的无约束优化方法

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系统工程与电子技术 2004年第2期26卷 248-252,267页

作者：罗新龙北京邮电大学信息工程学院北京100876

通过把一个无约束优化问题转化为一个等价的常微分方程,利用二阶半对角隐式Runge Kutta公式构造了求解无约束优化问题的LRKOPT算法。LRKOPT算法具有与IMPBOT方法相似的数值特性,但LRKOPT算法可以看成是最速下降方向与牛顿法方向的非线... 详细信息

通过把一个无约束优化问题转化为一个等价的常微分方程,利用二阶半对角隐式Runge Kutta公式构造了求解无约束优化问题的LRKOPT算法。LRKOPT算法具有与IMPBOT方法相似的数值特性,但LRKOPT算法可以看成是最速下降方向与牛顿法方向的非线性组合,而IMPBOT方法为它们两者之间的线性组合。在目标函数为一致凸函数的假设条件下,证明了LRKOPT方法的具有全局收敛和局部超线性收敛性。数值结果表明LRKOPT方法具有很好的数值稳定性并且LRKOPT方法的计算效率优于IMPBOT方法。

关键词：全局收敛超线性收敛对角隐式Runge-Kutta公式无约束优化 LRKOPT算法

The User-level Security of Mobile communication Systems

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The Journal of china Universities of posts and telecommunications 2002年第3期9卷 62-69页

作者： DUAN Lian, ZHANG Hao liang, WU Wei ling (information engineering school,{3. University of posts and telecommunications,beijing 100876, P.R. china) information engineering school Beijing University of Posts and TelecommunicationsBeijing 100876 P.R. China

This paper studies the user-level security of mobile systems . The currentmobile phone users trust the invisible security of the 2G systems. The evolution from thesecond-generation mobile systems (2G) to the third generation systems (3.) will introduce thethreats and opportunities of the Internet to the world of mobile communications. From the technicalpoint of view, the new security requirements are similar to the security requirements met with todayin a company Intranet environment. There is, however, one great difference; the charge paid foraccessing the service. In future the users of mobile systems will have to be more aware of thesecurity issues.

关键词： security mobile communication system user

AN EFFICIENT MOTION ESTIMATION ALGORITHM FOR H.264/AVC H.264/AVC

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AN EFFICIENT MOTION ESTIMATION ALGORITHM FOR H.264/AVC H.264...

Capacity analysis and optimal power allocation for coordinated transmission in MIMO-OFDM systems

中国通信学会第六届学术年会

作者： Guo Yanjie~1,Liu Ruifang~2 (1 school of information and communication {3.,beijing University of posts and telecommunications,beijing 100876,china 2 school of information and communication engineering,beijing University of posts and telecommunications,beijing 100876,china)

Motion estimation plays an important role in the video compression standard,such as H.263.MPEG-2/4 and *** search(FS) is the most common and simple motion estimation algorithm,but owing to the FS algorithm resulting in huge computational complexity,so many fast motion estimation algorithms have been proposed instead of *** the paper,we discuss UMHexagonS algorithm, then we propose a fast ME algorithm based on *** simulation results show that proposed algorithm maintains an unnoticeable quality loss in terms of PSNR on average compared to FS and UMHexagonS but reduces motion estimation time.

关键词：

来源： cnki会议评论

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Science china(information Sciences) 2012年第6期55卷 1372-1387页

作者： CUI QiMei 1,HUANG XueQing 1,LUO Bing 1,TAO XiaoFeng 1 & JIANG Jun 2 1 Key Laborary of Universal Wireless communications,beijing University of posts and {3.,beijing 100876,china 2 StarPoint communication Software Company Ltd.,beijing 100102,china 1. Key Laborary of Universal Wireless communications Beijing University of Posts and Telecommunications Beijing 100876 China2. StarPoint Communication Software Company Ltd. Beijing 100102 China

Coordinated transmission in multicell coordination networks has attracted much attentions in recent *** the paper,we investigate one open problem in the above area,which is concerned with how to solve the closed-form optimal power allocation scheme of coordinated transmission in downlink orthogonal frequency-division multiplexing (OFDM) systems with multiple antenna configurations and individual power constraints.A frequency-selective fading multiple-input multiple-output (MIMO) channel is *** derive the closed-form solutions of sum-rate capacity and optimal power allocations for coordinated transmission under the diversity case and the multiplexing case by solving the constrained optimization *** simulations are performed to verify the derived theoretical conclusions by means of comparing the proposed optimal power allocation (OPA) scheme with the other two typical power allocation *** is the power allocation scheme combining traditional water-filling with equal power (WS-EF PA).The other is equal power allocation (EPA) scheme.

关键词： coordinated multi-point transmission multicell cooperation capacity analysis MIMO-OFDM power allocation frequency selective MIMO channel

High Performance Speech Compression System

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Journal of University of Science and Technology beijing 2001年第3期8卷 229-233页

作者： Ke Liu, Zhichun Mu, Zhong Wang information engineering school, University of Science & Technology {3., {3. 100083. china Univ Sci & Technol beijing Informat Engn Sch Beijing 100083 Peoples R China

Since Pulse Code Modulation emerged in 193., digitized speech has experienced rapid development due to its outstanding voice quality, reliability, robustness and security in communication. But how to reduce channel width without loss of speech quality remains a crucial problem in speech coding theory. A new full-duplex digital speech communication system based on the Vocoder of AMBE-1000(TM) and microcontroller ATMEL 89C51 is introduced. It shows higher voice quality than current mobile phone system with only a quarter of channel width needed for the latter. The prospective areas in which the system can be applied include satellite communication, IP Phone, virtual meeting and the most important, defence industry.

关键词： digital signal processing digital speech compression digital communication full-duplex coding rate

Spectral integration and perception of Chinese back vowel /γ/

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Science china(information Sciences) 2010年第11期53卷 2300-2309页

作者： YU ShuiYuan1, CHEN YuDong2 & WU JieRu3.1school of Computer, communication University of china, {3. 100024, china 2International College for Chinese Language Studies, communication University of china, {3. 100024, china 3.0} of Presentation Art, communication University of china, {3. 100024, china 1. school of Computer Communication University of China Beijing 100024 China2. International College for Chinese Language Studies Communication University of China Beijing 100024 China3. School of Presentation Art Communication University of China Beijing 100024 China

The first two formants of the back vowels of many languages, such as English, are often close in frequency within the critical 3.5-Bark distance and are phonetically equivalent to a single intermediate formant. This phenomenon is called spectral integration. The integrated spectral peak is related more directly to phonetic quality than to acoustic formants and is therefore an important cue for determining the phonetic quality of vowels. The Chinese vowel /γ/ is a back vowel, but its first two formants are commonly separated by more than the critical distance. What are the perceptual cues for this vowelDoes the spectral integration phenomenon influence its perceptionThis paper describes a series of identification experiments and rating experiments on the influences of the distance, spectral shape, and relative amplitude of the first two formants on the phonetic quality of /γ/. The results show that all stimuli with a two-peaked spectral shape are perceived as /γ/ whenever the first two formants are separated by the critical Bark distance or beyond. When the two formants are separated by roughly the critical distance, only those stimuli with sharp formants are perceived as /γ/, while stimuli with trapezoidal or single-peaked spectral shapes are not perceived as /γ/. Specifically, when the second formant is 10 dB higher than the first, the spectral integration phenomenon influences formant perception, and the stimulus is not perceived as /γ/; on the contrary, when the second formant is 0-20 dB lower than the first, the stimulus is perceived as /γ/, and spectral integration does not occur. That is to say, spectral integration occurs asymmetrically about the relative amplitudes of the first two formants. In a word, the Chinese vowel /γ/ is a back vowel, but spectral integration does not occur in the perception of its first two formants. Two individual formants are necessary for the phonetic color of the Chinese vowel /γ/. This vowel is different from the back vowels of w

关键词： spectral integration Chinese back vowel /γ/ back vowel critical distance

The Application of Graph Diffusion in High-level Feature Extraction

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The Application of Graph Diffusion in High-level Feature Ext...